1. Field
The present disclosure relates to a neural probe structure and a method for manufacturing the same, and more particularly, to a neural probe structure that is inserted into a human body to stimulate the nerves in the inserted body part by a magnetic field, and obtain signals generated from the stimulated nerves, and a method for manufacturing the same.
[Description about National Research and Development Support]
This study was supported by the Global Frontier Project of Ministry of Science, ICT and Future Planning, Republic of Korea (Project No. 1711025644) under the superintendence of National Research Foundation of Korea.
2. Description of the Related Art
Recently, to treat various brain diseases and understand the working mechanism of the brain, studies on technology to stimulate the cranial nerves with various stimulation means, and sense and analyze neural signals emitted from the cranial nerves due to the stimulation are being actively made.
Methods for stimulating the cranial nerves include electrical stimulation to stimulate the cranial nerves by applying an electric current, drug stimulation to stimulate the cranial nerves by injecting a fluid, optical stimulation to stimulate the cranial nerves with optical radiation, and magnetic stimulation to stimulate the cranial nerves by changing the strength of a magnetic field. The cranial nerves in a target site are artificially stimulated using the stimulation means, and in response, neural signals are emitted from the cranial nerves and collected.
Among the cranial nerve stimulation means, electrical stimulation, drug stimulation, and optical stimulation stimulates the cranial nerves by directly inserting a neural probe manufactured to a small scale via micromachining technique into the brain, to transmit each stimulation medium without causing great damage when inserted into the brain.
The electrical stimulation stimulates the cranial nerves by emitting electrical signals from electrodes connected up to the distal end of the neural probe. The drug stimulation stimulates the cranial nerves by injecting drugs into the brain through microfluidic channels formed in the neural probe. The optical stimulation stimulates the cranial nerves with light irradiation into the brain through an optical waveguide provided in the neural probe. As described above, it is possible to directly stimulate a target site through the neural probe inserted into the brain.
However, in the case of electrical stimulation, localizing stimulation of the cranial nerves is difficult because a material itself of which the brain is made is conductive, and there is a risk of damage to the cranial nerves. Furthermore, in the case of optical stimulation, stimulation of the cranial nerves with light irradiation requires transfection of specific genes that are activated and deactivated by a specific wavelength of light, leaving problems to be solved for future clinical applications.
On the other hand, among the conventional stimulation means, magnetic stimulation stimulates the cranial nerves from outside the skull through a magnetic stimulation device formed of a metal coil without insertion into the brain or other surgeries. The conventional magnetic stimulation has an advantage in stimulating the cranial nerves without causing damage to the brain.
However, because the conventional magnetic stimulation stimulates the cranial nerves by applying a magnetic field from outside the skull, localizing the stimulation of cranial nerves to a specific target site is very difficult. Especially, in the case of cranial nerve stimulation of deep brain regions, it is more difficult to increase focality of the magnetic stimulation.
Accordingly, there is a growing need for magnetic stimulation means for localizing stimulation of the cranial nerves to increase focality while minimizing cranial nerve damage caused by stimulation, and a method for manufacturing the same.